| MadSci Network: Chemistry |
OXIDATION IS LOSS OF ELECTRONS This is the basis of electrochemistry. This is, electricity and chemistry going together: using chemistry to produce electricity and using electricity to produce a chemical reaction. In electrochemistry we will always find that there is one species that losses electrons (gets oxidized), electrons that will be gained by another one (which gets reduced, we say). That is why we call these redox (RED for reduction, OX for oxidation) reactions. How easy or how hard is for the first species to loss electrons (or to gain them instead) when compared with the other one will determine their behavior as species to be respectively oxidized or reduced. We can translate into numbers the behavior of every chemical species (element, molecule or ion) in order to make the comparison. This number is the Reduction Potential [1]. With the reduction potential we can compare the the two elements to see which one will get reduced and which one oxidized [2-3] The rule is that the species with a more positive reduction potential will get reduced whilst the more negative value will be oxidized, whenever we put them in contact. The reduction potentials for silver and aluminium are: Silver +0.80 V [2] Aluminium -1.66 V [4] Therefore we can say that silver will be protected by aluminium because it will be the second of the metals the one that will get oxidized and not the silver. [1]http://en.wikipedia.org/wiki/Reduction_potential [2]http://en.wikipedia.org/wiki/Table_of_standard_electrode_potentials [3]Handbook of Chemistry and Physics: 88th Edition [4]http://www.jesuitnola.org/upload/clark/Refs/red_pot.htm
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